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In the present study, lignin and lignin-carbohydrate complex (LCC) constituting the cell wall structure of sesame hulls were investigated to explore novel techniques of dehulling. Milled wood lignin (MWL), Björkman LCC, and acid-soluble LCC (LCC-AcOH) were extracted from sesame hulls and characterized by carbohydrate composition analysis, molecular weight analysis, UV–vis spectroscopy, FT-IR, thermal analysis, Py-GC/MS, 2D HSQC NMR, and 31P NMR. The results showed that rhamnose accounted for the largest proportion of the lignin and LCC fractions, followed by glucose. Björkman LCC had the largest molecular weight, MWL had the smallest molecular weight, and LCC-AcOH had the largest polydispersity index. The lignin of sesame hulls consisted of syringyl (S), guaiacyl (G), p -hydroxyphenyl (H), and caffeyl alcohol (C) units. The most abundant monomer was guaiacyl (G), followed by caffeyl alcohol (C). C-type lignin is a new type of lignin that is different from the three traditional lignin monomers. The major lignin-linked bonds in the MWL and LCC-AcOH were β-O-4′ and β-β′, and β-5′ bonds were present in the Björkman LCC. The major LCC chemical bonds in the three fractions were PhGly. These findings will provide the factual basis for exploring different dehulling methods to enhance the quality of sesame products. • Lignin and LCC were isolated from the sesame hull firstly. • G/S-lignin and C-lignin were present in the sesame hulls. • The lignin-carbohydrate bonds in MWL, LCC-AcOH, and LCC were only PhGly. • The content of G-type lignin in sesame hulls was the highest, followed by C-type. [ABSTRACT FROM AUTHOR]

The objective of the present investigation was to extract pectic polysaccharides from sesame seed hull and to determine their physicochemical and functional characteristics. The pectic polysaccharides in the seed hull were extracted with HCl and then collected at three ethanol concentrations of 30% (SSP30), 50% (SSP50), and 90% (SSP90). We found that SSP30 represented 75.6% of the total polysaccharides, and that it contained 76.39% galacturonic acid, with many HG domains and few short side chains in the RG-I domains. SSP30 exhibited the strongest hydroxyl radical scavenging activity among the three fractions, and was better able to stabilize the emulsions. Higher Mw pectic polysaccharides were firstly precipitated at lower ethanol concentrations, and the Mw of the precipitated pectic polysaccharides decreased with increasing ethanol concentration. These results provide important information on the structure and functional characteristics of sesame hull polysaccharides. This information can contribute to the future development of sesame hull polysaccharides for industrial purposes. • Pectic polysaccharide (SSP30) was isolated from sesame seed hull at first time. • Physicochemical and functional properties of the pectin were characterized. • SSP30 fraction exhibited better able to stabilize the O/W emulsions. • SSP30 exhibited strong hydroxyl radical scavenging activity. [ABSTRACT FROM AUTHOR]

Varieties of plant species may affect the composition and structures of the polysaccharides, thus have an impact on their chemical properties and biological activities. Herein, the present study comparatively evaluated the differences in the chemical composition, morphological structures, antioxidant activity, and anti-inflammatory activity of the stem and peel polysaccharides from different varieties of pitaya. The FT-IR and NMR spectra indicated that the six polysaccharides had similar structural features, whereas the physicochemical characterization showed that they differed significantly in terms of the monosaccharide composition, molecular weight, and surface morphology. In addition, different varieties of pitaya polysaccharides exhibited different antioxidant activities and similar anti-inflammatory activities. These data suggested that varietal differences resulted in pitaya stem and peel polysaccharides with different monosaccharide compositions and molecular weights, thus led to different antioxidant activities and protection against oxidative damage, while similar structural features were closely related to their similar anti-inflammatory activities. Therefore, the study of the stem and peel polysaccharides from different varieties of pitaya can help us to better understand the relationship between their composition and structure and their biological activities. In addition, pitaya stem and peel polysaccharides have the potential to act as antioxidants or to treat inflammatory damage. [ABSTRACT FROM AUTHOR]